[css-gcpm-3] Fix refs to element() and running() (w3c#9319)

Author: cdoublev

css-gcpm-3/Overview.bs

@@ -247,7 +247,7 @@ The ''running()'' value
 
 <pre class="propdef partial">
 	Name: position
-	New Values: running()
+	New Values: <<running()>>
 </pre>
 
 
@@ -361,7 +361,7 @@ Just as with ''string()'', ''element()'' takes an optional keyword to describe w
 
 <pre class="propdef partial">
 	Name: content
-	New Values: element()
+	New Values: <<element()>>
 </pre>
 
 <pre class="prod">